Do defensive stats tell us anything worth knowing? Does having a defensive rating for players help us predict which teams will be most successful in keeping hits and runs off the scoreboard? That is a question that has never been answered, and one that I will try to explore. Previously, people have looked at how well defensive metrics correlate from year to year with themselves, and how well they correlate to other metrics. Going a bit deeper, people have shown that the metrics do not correlate as well for players who switch teams as they do for players who stay put. But what we really should want to know is how useful they are in predicting which teams keep hits and runs off the scoreboard.

The standard has to be team defensive efficiency record, a stat invented by Bill James that tells us simply how often a batted ball is turned into an out. This stat is not the sole responsibility of the fielders, ballparks have a big effect on it, as do the types of batted balls allowed by pitchers. Line drives usually become hits, popups are almost always outs. This also has to be accounted for before we can attribute DER to fielders.

What I have done is take simple defensive projections of 4 systems, UZR and PM (John Dewan's) which are found on Fangraphs, my own TotalZone, and Zone rating runs, using the method of Chris Dial, and data from the excellent replacement level Yankees website. The simple projection is a marcel-type where I weight 2008 as 5, 2007 as 4, 2006 as 3, and add in 1500 chances of league average for each player. Since 2008 has a weight of 5, a player who got 300 chances in 2008 and nothing before that will have his rating regressed 50% to the mean. These simple projections are prorated to the actual number of defensive innings for each team in the 2009 season. Finally, the projected team defensive ratings are compared to a park and BIP adjusted figure for team runs, based on their DER.

The results are disappointing. The correlation coefficients average only .02. I won't tell you which system wins yet for a few reasons. TotalZone is neither first nor last among the 4.

The first reason not to publish the results is that there is more work to do. I think I need to design a more robust projection system for this, accounting for data at multiple positions. For example, Franklin Gutierrez has a rating of close to +20 for 2006-2008, but as a right fielder since that is where he mostly played for Cleveland. He played center last year for Seattle and was the defensive star of 2009. But without data in center, right now I have all the projections expecting him to be average. There is a simple solution, use the position adjustments to derive a CF projection from his RF data, but that will take a little time to program in and do it for all 4 defensive systems.

While I work on the data and towards a more robust test, I will invite anyone else who does defensive ratings to join the test. You'll just need to provide the data for 2006 to 2008, along with a MLBAM ID for each player. The format needed is like this, an example used is Adam Everett 2006:

MLBID,POS,Chances,Runs,Stat,Year

276361,6,340,43.9,TZ,2006

I'll add any system to the mix as long as you provide me the data in the proper format. In particular, I'd love to have Dave Pinto's PMR, Shane Jensen's safe, Peter Jensen's Big Zone, and Tango Tiger's Fan Scouting report, if the creators of those systems are willing.

Getting more for Cliff Lee than the Mariners gave up for him would seem to be an easy task. Earlier today it looked like the Mariners had done very well for themselves, Landing Jesus Montero from the Yankees. Montero is not a perfect prospect, his hitting in AAA is not what was expected and defensively, few think he'll stay at catcher. Still, we're talking about a 20 year old who split time between A+ and AA last year, hitting 337/389/562. He's a potential Carlos Delgado at the plate. Baseball America still rates him the #5 prospect in the game. The other two prospects were not as good, but if you can get a guy like Montero for 3 months of Lee, I don't see how you pass that up.

Instead, they take the Rangers offer headed by Justin Smoak. Smoak is a fine prospect himself despite struggling in the majors so far. Baseball America rated him #13 preseason. He's a patient hitter, a big strong guy, and a decent defender at first. He hasn't shown a lot of power yet. I don't think you can just assume a big hitter with a good swing and eye will develop power. Look at Casey Kotchman. Another comparable prospect who looked great at AA with a lot of walks, but has been only average in the big leagues, is Jeremy Hermida. There are comparables who turned out better, maybe Joey Votto. I just think Montero, 3 years younger, has a much better chance of being an impact hitter.

If they got a lessor frontline prospect, did they at least make up for it in quantity?

Doesn't look like it. Blake Beavis, settle down, I mean Blake Beavan, is a 6'7 250 pounder who doesn't walk anybody, but doesn't strike anyone out either. He ranked #17 for the Rangers in preseason. Matt Lawson is a 24 year old AA second baseman. Looking at his batting average, contact rate, power, and speed I don't see anything he'd be major league average in offensively. He's not super young either. His defense is outstanding by TotalZone, +19 last year after +12 in 2008. Looks like a utility infielder to me. He did not rank among Texas's top 30. The final guy, Josh Lueke, is a 25 year old AA reliever with very good strikeout rates. He also did not rank among the top 30. That's not all though. Hard to see how any team would accept him in a trade until a rape case against him gets resolved.

Edit: The link I saw describing the charges against him was a year old. He took a plea deal and the matter is in the past. Still wouldn't want him on my team though.

Who won the trade? I'd say the Yankees. They get to keep Montero and will have Cliff Lee in 2011 anyway.

I'm doing this partly because, while reading today's Cliff Lee rumors, MLBTR says the Mariners are seeking a stud catcher close to MLB ready. So I thought I'd look at my database and see who qualifies.

MLB studs:

Buster Posey, Matt Wieters, Carlos Santana. Despite not having the same level of hype, this year's pair of rookies have quickly established their bats are superior to Oriole Jesus. It's still too early to give up on Wieter's bat though, and for a catcher he's not terrible. Plus, he is an outstanding defender. None of these guys are going anywhere.

Montero is the one with the highest upside, but may not stick at catcher. Cervelli and Marson are capable big league receivers but lack power. Lucroy and Castro look like they can field the position and have offensive potential. The others need work with the glove but could be good hitting catchers. Conger, at 22, is younger than this group other than Montero. He's already in AAA, walks as often as he strikes out, and has shown power potential in the past. He hasn't hit the ball very hard this year though, and still has a lot of work to do on defense.

Salty has to recover from Mackey Sasser disease. Flores looked very promising but hasn't played this year after shoulder surgery. Arencibia has big numbers in AAA this year, but is doing it in an extreme hitter's park. CHONE is not convinced he's for real.

Which players could be offered in a trade? Depends a lot on where his team ranks in the standings. I'd say:

I've made the stat more accurate by adding information from MLB Gameday hit location. The numbers on my player pages, and at Baseball-reference and Fangraphs, do not reflect the new methodology though at some point they should.